TITLE:   GCN CIRCULAR
NUMBER:  44475
SUBJECT: Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
DATE:    26/05/05 15:28:39 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

A bright burst from SGR 1E1841-045
(IPN triangulation: Ridnaia et al., GCN 44448;
SVOM-GRM detection: Zao et al., GCN 44450) 
triggered Konus-Wind at T0=20396.052 s UT (05:39:56.052)
on 2026 May 2.

The burst light curve shows a single pulse,
which starts at ~T0-50 ms and has a total duration of ~96 ms.
The emission is seen up to ~200 keV.

The Konus-Wind light curve of this burst is available at
http://www.ioffe.ru/LEA/SGRs/260502_T20396/

As observed by Konus-Wind, the burst
had a fluence of 8.64(-0.45,+0.46)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.004 s,
of 1.93(-0.16,+0.16)x10^-5 erg/cm2/s
(both in the 20 - 500 keV energy range).

The spectrum of the burst
(measured from T0 to T0+0.064 s)
is best fit in the 20 - 500 keV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = 0.16(-0.69,+0.76)
and Ep = 48(-4,+3) keV (chi2 = 12/15 dof).

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.